Cultured corneal endothelial cell layers will be tested for active transport activity and attempts made to stimulate it. The use of such layers formed on gelatin membranes for corneal graft material in rabbits will be pursued. The transport of labeled solutes between endothelial cells and the surrounding media will be tested by cryofixation of the layer. A search for the substance provoking the vascularization of the cornea will be made by testing the activity of epithelial cell extracts, both in vitro on cultured vascular endothelial cells and in vivo by perfusing the cornea with a minipump.